The present invention relates to a side vehicle-body structure of an automotive vehicle which comprises a side door provided to open and close an entrance portion formed at a vehicle-body side face portion.
In the automotive vehicle provided with a rear side door to open and close an entrance portion for a rear seat, a peripheral portion of the rear-seat entrance portion at the vehicle-body side face portion serves as a door reception portion for receiving a peripheral portion of the rear side door from the inside. In this kind of vehicle, there have been conventionally provided various countermeasures for suppressing the rear side door from being deformed toward an inside of a cabin when the rear side door receives an impact load from a vehicle-body side or suppressing a rear body from being deformed toward the inside of the cabin when the rear body receives the impact load by way of the rear side door, thereby protecting a passenger seated in the rear seat.
Japanese Patent Laid-Open Publication No. H5-069859, for example, discloses a side vehicle-body structure comprising a reinforcing member (side sill reinforcement) which extends along a lower edge portion and a rear edge portion of an entrance portion for a rear seat. The reinforcing member comprises a straight portion extending in a vehicle longitudinal direction along the lower edge portion of the rear-seat entrance portion and a curve portion curving obliquely rearward and upward from a rear end of the straight portion along the rear edge portion of the rear-seat entrance portion and an upper face of a rear wheelhouse.
In the side vehicle-body structure of the above-described patent document, the lower edge portion of the rear-seat entrance portion is formed by a side sill. The above-described straight portion of the reinforcing member forms two closed cross sections therein by being interposed between a side sill inner and a side sill outer which constitute a side sill, and is joined to a lower end portion of a center pillar reinforcement at its front end portion. Further, a vehicle-body side face portion which forms the rear edge portion of the rear-seat entrance portion is comprised of a side outer panel as a vehicle-body outer panel exposed to the outside of a cabin and a side inner panel arranged inside of the side outer panel, and the curve portion of the above-described reinforcing member is provided between these panels. This curve portion is joined to an outside of the side inner panel, thereby forming a closed cross section together with the side inner panel, and joined to a suspension-housing reinforcement at its rear end portion.
The reinforcing member provided at the door reception portion of the vehicle body can disperse the impact load to various parts of the vehicle body by receiving the impact load inputted to the rear side door from the vehicle-body side and transmitting that to the center pillar reinforcement and the suspension-housing reinforcement, and can absorb an impact energy by being compressed and crushed in a vehicle width direction. Thus, load dispersion to the various parts of the vehicle body via the reinforcing member and impact absorption by deformation of the reinforcing member are performed compatibly, so that the rear side door can be effectively suppressed from coming in toward an inside of the cabin.
Further, Japanese Patent Laid-Open Publication No. 2008-081035 discloses a structure in which an engaging pin provided at a rear lower end portion of a rear side door and an engagement hole provided at a door reception portion on the vehicle-body side are engaged with each other when the rear side door is closed.
Since a move of the rear end portion of the rear side door which is engaged with the vehicle-body side relative to the vehicle body is limited as described above, deformation of the rear side door, such as the rear side door's coming in toward the inside of the cabin, can be restrained.
However, according to the structure disclosed in the above-described first patent document, only the single reinforcing member is joined to the vehicle-body outside of the side inner panel at the rear edge portion of the rear-seat entrance portion, so that it is difficult to compatibly achieve the load transmission performance and the impact absorption performance for the following reasons.
First, in a case in which the width, in the vehicle width direction, of the closed cross section formed between the side inner panel and the reinforcing member is shortened for the purposed of restraining buckling of the reinforcing member which may damage the load transmission performance, a width, in the vehicle width direction, of a gap formed between the side outer panel as the vehicle-body outer panel and the reinforcing member increases. Therefore, the amount of move of the rear side door which comes in toward the inside of the cabin from a point where the rear side door comes to contact the side outer panel to another point where the rear side door comes to contact the reinforcing member, without substantially crushing the reinforcing member, (insubstantial-stroke amount) increases. Further, the crushing amount of the reinforcing member in the vehicle width direction is limited, so that an impact absorption effect caused by crushing of the reinforcing member decreases.
To the contrary, in a case in which the width, in the vehicle width direction, of the closed cross section formed between the side inner panel and the reinforcing member is lengthened for the purpose of increasing the crushing amount of the reinforcing member, the reinforcing member tends to have buckling at a local portion, in a longitudinal direction, thereof. In particular, since a portion of the reinforcing member which contacts an impact bar provided at the rear side door locally receives a large load, the buckling tends to occur at this portion of the reinforcing member. This occurrence of the buckling of the reinforcing member damages the load transmission performance of the reinforcing member, so that the load dispersion to the various parts of the vehicle body is not performed effectively.
While some reinforcement countermeasures, such as increasing a plate thickness of the reinforcing member or adding a new reinforcement in the closed cross section, are further required in order to solve the above-described problem, there occurs a new problem that the weight of the vehicle body may increase improperly.
Further, in the structure disclosed in the above-described second patent document in which the rear door is suppressed from coming in toward the inside of the cabin by engagement of the rear side door with the door reception portion, some countermeasures, such as adding a new member for performing the energy absorption or the load transmission to the door reception portion, are required in order to absorb the impact energy or disperse the load to the parts of the vehicle body when the impact load is inputted from the vehicle-body side. This may cause an increase of the vehicle-body weight as well. Moreover, providing the engaging pin projecting toward the inside of the cabin at the rear side door may be inappropriate from a design perspective or the like.